From Billboard by way of Pitchfork... hadn't seen this mentioned previously.

Columbia/Legacy will reissue still-living ladies' man Leonard Cohen's first three albums with previously unreleased tracks on April 24, according to a report from Billboard.com.

1968's Songs of Leonard Cohen will come with incomplete tracks "Store Room" and "Blessed Is the Memory". 1969's Songs From a Room will include early takes of "Bird on a Wire" and "You Know Who I Am", titled "Like a Bird" and "Nothing to One", respectively, with the latter featuring harmonies by David Crosby. And finally, 1971's Songs of Love and Hate will come with a full-band version of "Dress Rehearsal Rag".

Columbia/Legacy will also re-release Anjani Thomas' 2006 album Blue Alert on April 24, which features songs co-written by Field Commander Cohen. The re-released version of the record features a DVD with videos for "Thanks for the Dance" and "The Mist".

Just received the Leonard Cohen reissues from Amazon USA (plus Twelve - Patti Smith; Crystal Caves - Stevie Nicks; Greatest Hits I & II - Linda Ronstadt).

I have not heard SONGS FROM A ROOM yet. There's nothing mentioned that David Crosby sings harmony on Nothing To One; however it is mentioned that both the bonus songs on this CD were Recorded May 1968 and Produced by DAVID CROSBY.

I will confirm if David Crosby sings harmony when I listened to the CD.

David Crosby (I assume) does sing backing harmonies on "Nothing to One"